Umbilical vein as ureteral replacement.

In 13 dogs the middle one-third of the ureter and in four dogs the entire ureter was replaced by fresh Rhesus monkey or human umbilical cord vein. The overall success rate was 60 per cent (10/17); one dog revealed an excellent intravenous pyelogram; the typical roentgenographic appearance of the kidney was a slight hydronephrosis. Animals surviving for more than 1 year were nephrectomized on the contralateral side. One dog is still alive at 36 months. Histologically, the typical structures of the umbilical vein remained unchanged after 2 years, but endothelium was replaced by urothelium. The umbilical vein seems to be an embryonic tissue of extremely low antigenicity and therefore suitable for transplantation.